Chemical composition and in vitro antioxidative activity of a lemon balm (Melissa officinalis L.) extract

The leaf material of lemon balm (Melissa officinalis L.) was extracted with 450 ml/l aqueous ethanol by medium pressure liquid-solid extraction. The total phenolic content of the extract was estimated as gallic acid equivalents by Folin-Ciocalteu reagent method and a qualitative-quantitative compositional analysis was carried out using high performance liquid chromatography coupled with photodiode array detection. The lemon balm extract contained hydroxycinnamic acid derivatives and flavonoids with caffeic acid, m-coumaric acid, eriodictyol-7-O-glucoside, naringin, hesperidin, rosmarinic acid, naringenin, hesperetin being identified based on their chromatographic behaviour and spectral characteristics. The extract was also investigated for potential in vitro antioxidant properties in iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate), superoxide anion and nitric oxide free-radical scavenging, and inhibition of β-carotene-linoleic acid bleaching assays. The extract demonstrated antioxidant activity in all the assays. However, it was not as potent as the positive controls except in the β-carotene-linoleic acid bleaching assay, where its activity was superior to that of gallic and caffeic acids and statistically indistinguishable from quercetin and BHA. The exceptionally high antioxidant activity and the fact that this assay is of biological relevance warrants further investigation of lemon balm extract in ex vivo and in vivo models of oxidative stress.     

A comparison between bark extracts from Pinus pinaster and Pinus radiata: Antioxidant activity and procyanidin composition

The composition and antiradical activity of procyanidins from the bark of two kinds of pine, Pinus pinaster and Pinus radiata, were compared. Both the total bark extract and the fraction soluble in both water and ethyl acetate (OW) were evaluated, because of their promising results in previous experiments.     

Chemical composition and antioxidative activity of Moldavian balm (Dracocephalum moldavica L.) extracts

Moldavian balm (Dracocephalum moldavica L., Lamiaceae) is a perennial herb native to central Asia and naturalized in eastern and central Europe. It is commonly consumed as a food-related product and as a herbal preparation because of its reputed medicinal properties. Despite its importance, few reports exist in the literature regarding the chemistry or antioxidant activity of this species. In this study, the aerial material of Moldavian balm collected from Iran was extracted by Soxhlet using seven solvents of different polarity, viz., petroleum ether, dichloromethane, acetonitrile, ethyl acetate, methanol, n-butanol and water. The qualitative-quantitative chemical composition of each extract was determined using high-performance liquid chromatography coupled to photodiode array detection. For each extract, the total phenolic content was estimated as was the in vitro antioxidant activity using the iron(III) reduction assay, the β-carotene-linoleic acid bleaching assay and the 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) free radical scavenging assays. Hydroxylated cinnamic acids, their derivatives and flavonoids were identified and quantified within the extracts, with rosmarinic acid being the most abundant component identified. The extracts demonstrated different degrees of potency within each assay, however, the observed pattern was not necessarily replicated between assays indicating the importance of the use of more than one screening technique to estimate the antioxidant activity of plant extracts.     

Chemical composition,anthocyanins, non-anthocyanin phenolics and antioxidant activity of wild bilberry (Vaccinium meridionale Swartz) from Colombia

Berries of Vaccinium meridionale Swartz native to Colombia were analysed for chemical composition, total phenolic content, anthocyanin content, and antioxidant activity. In addition, high-performance liquid chromatography with photodiode array detection (HPLC–DAD) and HPLC-electrospray ionisation tandem mass spectrometry (ESI–MS/MS) were used to determine anthocyanin and phenolic composition. Anthocyanin content was 329.0 ± 28.0 mg cyanidin 3-glucoside equivalents/100 g (fresh weight) FW and total phenolic content was 758.6 ± 62.3 mg gallic acid equivalent/100 g FW. Cyanidin 3-galactoside was the major anthocyanin while the most abundant non-anthocyanin phenolic was chlorogenic acid.     

Chemical composition, mineral content and antioxidant activity of Verbena officinalis L.

Aqueous and hydroalcoholic extracts from Verbena officinalis L. were obtained and characterised. The analysis by HPLC-DAD and LC-MS allowed the detection and identification of three iridoids, fifteen flavonoids and four phenolic acid derivatives. Four flavonoids, scutellarein 7-diglucuronide (9), scutellarein 7-glucuronide (13), pedalitin 6-galactoside (15) and scutellarein 7-glucoside (19) are reported for the first time from this plant. In addition, three new flavonoids have been isolated: scutellarein 7-O-(2-O-feruloyl)-diglucuronide (5), pedalitin 6-O-diglucuronide (6) and pedalitin 6-O-(2-O-feruloyl)-diglucuronide (13). To our knowledge, these flavonoids have not been reported as natural products. Both extracts showed significant antioxidant activity using three in vitro model systems and the results have been correlated with total phenolic and total flavonoid contents. The results have allowed establishing an important relation structure-activity and significant correlations have also been found between the mineral content and the flavonoids present in both extracts.     

Juniperus sibirica Burgsdorf. as a novel source of antioxidant and anti-inflammatory agents

In order to examine antioxidant properties of methanol extracts of cones and needles of the unexplored Juniperus sibirica Burgsdorf. (Cupressaceae) species, various assays which measure free radical scavenging ability were carried out: DPPH, hydroxyl, superoxide anion and nitric oxide radical scavenger capacity test and reducing power (FRAP) assay. In all of the tests the extracts showed a potent antioxidant effect compared with BHT, a well-known synthetic antioxidant. In addition, the anti-inflammatory activity considering inhibitory potency toward COX-1 and 12-LOX was observed. Both extracts showed markedly anti-inflammatory activity, with needles having somewhat higher potency concerning both assays, reaching IC₅₀ at 1.29 mg/mL towards COX-1 and IC₅₀ at 1.34 mg/mL towards 12-LOX. Besides, in the extracts examined the total phenolic and flavonoid amounts were also determined, together with presence and content of the selected flavonoids: luteolin-7-O-glucoside, apigenin-7-O-glucoside, luteolin, apigenin, rutin and quercetin, which were studied using LC–MS/MS technique. LC–MS/MS analysis showed a noticeable content of natural products according to which the examined J. sibirica Burgsdorf. species could well be regarded as a promising new source of bioactive natural compounds, which can be used both as a food supplement and a remedy.     

In vitro antioxidative activities of extract and semi-purified fractions of the marine red alga, Rhodomela confervoides (Rhodomelaceae)

The methanol–chloroform extract of the marine red alga, Rhodomela confervoides, was measured for antioxidant activity, using the α,α-diphenyl-β-picrylhydrazyl radical-scavenging assay and the β-carotene-linoleate bleaching assay systems, and compared with those of the positive controls of butylated hydroxytoluene, gallic acid and ascorbic acid. The active extract was further purified by liquid–liquid partition to afford four fractions, of which the ethyl acetate-soluble (EA) fraction exhibited the strongest antioxidant activity in both assay systems. This fraction was further divided into seven subfractions, designated as EA1–EA7, by silica gel vacuum liquid chromatography. In most cases, EA1 and EA4 were found to possess the strongest activity. The total phenolic contents and reducing powers of the extract, fractions, and subfractions were also determined. Significant associations between the antioxidant potency and the total phenolic content, as well as between the antioxidant potency and the reducing power, were found for the tested fractions and subfractions.     

Polyphenol contents and in vitro antioxidant activities of lyophilised aqueous extract of kiwifruit (Actinidia deliciosa)

The aim of this study was to determine the antioxidant potency and total phenolic and flavonoid contents of kiwifruit (Actinidia deliciosa) in vitro by analysing the radical scavenging activity of lyophilised water extract from kiwifruit (LEK) for 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), and superoxide anion radical (O₂⁻) as well as the total reducing power by FRAP and CUPRAC assays and the metal chelating activities. LEK showed efficient radical scavenging activity with DPPH, ABTS, DMPD, and O₂⁻ radicals; ferric (Fe³⁺) and cupric (Cu²⁺) ion reducing power and metal chelating activities. Moreover, the amounts of phenolic compounds, such as caffeic acid, ferulic acid, syringic acid, ellagic acid, catechol, pyrogallol, p-hydroxy benzoic acid, vanillin, p-coumaric acid, gallic acid, quercetin, ??-tocopherol and ascorbic acid, in LEK were quantified by LC-MS-MS. The results show that pyrogallol (2070.0 mg/kg LEK) is the main phenolic compound responsible for the antioxidant and radical scavenging activities of LEK. Finally, total phenolic and flavonoid contents were determined as gallic acid (GAE) and quercetin equivalents (QE). The GAE and QE values in LEK were 16.67 ± 2.83 ??g GAE/mg and 12.95 ± 0.52 ??g QE/mg, respectively. The results suggest that consumption of kiwifruit (A. deliciosa) can be beneficial effects due to its antioxidant properties.     

Chemical composition and antioxidant activity of Gaylussacia brasiliensis (camarinha) grown in Brazil

This paper presents the centesimal and mineral composition, fatty acid profile of the lipidic fraction, phenolic and anthocyanin contents, and antioxidant activity of Gaylussacia brasiliensis fruit. The results indicated the following composition: moisture (81.30%), lipids (0.62%), proteins (0.56%), carbohydrates (10.74%), dietary fiber (6.53%), and ash (0.25%). The main elements comprising the mineral composition were K, Mg, Ca, and Fe. The fatty acid composition was characterized by a high content of polyunsaturated fatty acids (62.2%) and a high PUFA/SFA ratio (2.92). The G. brasiliensis fruit contained considerable amounts of phenolics (492.87 mgAG/100 g) and anthocyanins (240.43 mg/100 g), which contribute to its high antioxidant activity. This study highlights the potential of this fruit as an important source of both nutritional and bioactive compounds available in the native Brazilian flora.     

Chemical composition and biological activities of Algerian Thymus oils

The compositions of essential oils isolated from nine samples of three Thymus species (Thymus algeriensis, Thymus pallescens and Thymus dréatensis) were analysed by GC and GC–MS, and a total of 114 components were identified. T. pallescens collected from various regions showed a great similarity in their compositions and were characterised by carvacrol (44.4–57.7%), p-cymene (10.3–17.3%) and γ-terpinene (10.8–14.2%) as the major components for four samples; only one sample was thymol-rich (49.3%) with a small amount of carvacrol (9.0%). On the other hand, T. algeriensis showed a chemical polymorphism, even for samples from the same location, and two new chemotypes for this species were proposed. Oxygen-containing monoterpenes were the predominant class (76.3%) in T. dreatensis oil, with linalool (30.4%), thymol (20.2%) and geraniol (19.6%) as the principal constituents. The oils were screened for their possible antioxidant activities by four complementary assays, namely DPPH free radical scavenging, hydroxyl radical scavenging, inhibition of lipid peroxidation and reducing power. The two new chemotypes of T. algeriensis exhibited strong hydroxyl radical scavenging (IC₅₀ = 2.2–3.3 μg/ml), but were not or only slightly active against the other radicals and exhibited a weak reducing power. Despite their chemical similarity, T. pallescens oils sometimes produced significant differences in their antioxidant activities. The essential oils were also screened for their antimicrobial activity against five bacteria (three Gram-positive and two Gram-negative) and one yeast (Candida albicans). The tested essential oils showed antimicrobial activity against the microorganisms used, in particular against two important pathogens, C. albicans and Helicobacter pylori.     

Chemical composition,cytotoxic and antioxidant activity of the leaf essential oil of Photinia serrulata

The leaf essential oil of Photinia serrulata was obtained by hydrodistillation and analyzed by GC and GC-MS. Seventy-one components were identified in the essential oil and the main components of the oil were 10-epi-γ-eudesmol (12.72%), pinene (6.85%), sabinene (5.93%), α-humulene (5.87%) and α-thujene (5.47%). The in vitro cytotoxicity of the oil on human cancer cell lines Hela, A-549 and Bel-7402 was examined. The oil was found to be very active against all the three human tumor cell lines tested with low IC₅₀ of 0.0427 μl/ml (Hela), 0.0219 μl/ml (A-549) and 0.0301 μl/ml (Bel-7402). The oil was also found to possess antioxidant activity as demonstrated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method.     

Chemical composition and antioxidant activity of the essential oil of Clinopodium vulgare L.

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil of Clinopodium vulgare. GC–MS analysis of the oil resulted in the identification of 40 compounds, representing 99.4% of the oil; thymol (38.9%), γ-terpinene (29.6%) and p-cymene (9.1%) were the main components. The samples were subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, IC₅₀ value of the C. vulgare essential oil was determined as 63.0 ± 2.71 μg/ml. IC₅₀ value of thymol and γ-terpinene, the major compounds of the oil, was determined as 161 ± 1.3 μg/ml and 122 ± 2.5 μg/ml, respectively, whereas p-cymene did not show antioxidant activity. In β-carotene-linoleic acid system, C. vulgare essential oil exhibited 52.3 ± 1.19% inhibition against linoleic acid oxidation. In both systems, antioxidant capacities of BHT, curcumine and ascorbic acid were also determined in parallel experiments.     

Antioxidant and antidiabetic activity of Dangyuja (Citrus grandis Osbeck) extract treated with Aspergillus saitoi

Dangyuja is a citrus fruit of Cheju Island in Korea, which is known to have a high content of flavanone glycosides, such as naringin and neohesperidin. Flavanone glycosides of Dangyuja (Citrus grandis Osbeck) extract were converted into their aglycones by naringinase and hesperidinase, and into their hydroxylated forms by Aspergillus saitoi.Dangyuja extract treated with A. saitoi had significantly higher antioxidant and antidiabetic activity than both its glycosides and aglycones in oxygen radical absorption capacity (ORAC) and supercoiled DNA strand scission assay, rat intestinal α-glucosidase and porcine pancreatic α-amylase inhibition, suggesting that the fermentation of flavanone aglycones of Dangyuja extract with A. saitoi can increase antioxidant and antidiabetic activity, compared to their glycosides and aglycones. This result suggests that Dangyuja extract prepared with enzymatic and microbial treatments could be used for the development of pharmaceutical foods to control the blood glucose level of diabetic patients by inhibiting α-amylase and α-glucosidase in the intestinal tract.     

Phytochemicals and antioxidant activity of different parts of bambangan (Mangifera pajang) and tarap (Artocarpus odoratissimus)

Mangifera pajang (family: Anacardiaceae; local name: bambangan) and Artocarpus odoratissimus (familiy: Moraceae; local name: tarap) are popular edible fruits in Sabah, Malaysia. The flesh, kernel and peel from M. pajang; seed and flesh from A. odoratissimus were analysed for total antioxidant activity, total polyphenol, total flavonoid and total anthocyanins contents. M. pajang kernel extract displayed the highest free radical scavenging and ferric reducing activities. Total phenolic content of the samples were in the range of 5.96–103.3 mg gallic acid equivalent/g. M. pajang kernel and M. pajang flesh contained the highest and lowest total flavonoid content with the values of 10.98 and 0.07 mg rutin equivalent/g, respectively. The antioxidant activities of extracts were significantly correlated with the total phenolic and flavonoid content (but not the anthocyanins content). The phytochemicals and antioxidant properties of M. pajang and A. odoratissimus, especially their by-products (kernel/seed), indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidant-rich nutraceuticals.     

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.     

Constituents of Sideritis syriaca. ssp. syriaca (Lamiaceae) and their antioxidant activity

The aerial parts of Sideritis syriaca ssp. syriaca (Lamiaceae) were extracted, after defatting, with diethyl ether, ethyl acetate and n-butanol. The antioxidant activities of the extracts were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picryl hydrazyl (DPPH) and Co(II) EDTA-induced luminol chemiluminescence. In both model systems the ethyl acetate extract was the most effective. Phytochemical analysis of ethyl acetate extract showed the presence of two new isomeric compounds (1 and 1′), identified as 1-rhamnosyl, 1-coumaroyl, dihydrocaffeoyl, protocatechuic tetraester of quinic acid, as well as chlorogenic acid (2), apigenin 7-O-glucoside (3), apigenin (4), 4′-O-methylisoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (5), isoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (6), 4′-O-methylisoscutellarein 7-O[β-d-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (7) and 4′-O-methylisoscutellarein 7-O-[β-d-allopyranosyl-(1 → 2)-6′′-O-acetyl-β-d-glucopyranoside] (8). The above compounds were identified by spectroscopic methods.     

Purification,composition analysis and antioxidant activity of a polysaccharide from the fruiting bodies of Ganoderma atrum

A water-soluble protein-bound polysaccharide was extracted from the fruiting bodies of Ganoderma atrum and isolated by gel-filtration chromatography. Its primary structural features and molecular weight were characterized by infrared spectrometry, gas chromatography, size exclusion chromatography, amino acid analyzer and high-performance liquid chromatography (HPLC). The data obtained indicated that the glycoprotein contains 10.1% of protein and 17 general amino acids and it is rich in glutamic acid, asparagic acid, alanine, glycine, threonine, and serine. It was mainly composed of mannose, galactose and glucose in a molar ratio of 1:1.28:4.91, with an average molecular weight of about 1013 kDa. The existence of an O-glycosidic linkage in PSG-1 (polysaccharide1) was demonstrated by a β-elimination reaction. The antioxidant activity of the purified polysaccharides was evaluated in vitro by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay, self-oxidation of 1,2,3-phentriol assay. Those various antioxidant activities were compared to standard antioxidants vitamin C and BHT. It was found that the scavenging effects of the purified polysaccharides increased with measuring concentration. The results indicated that the purified polysaccharides showed strong DPPH free radical and superoxide anion radical scavenging activities. This study suggested that the purified polysaccharides could potentially be used as natural antioxidants.     

Antioxidant activity of ethanolic extract of Cortex fraxini and use in peanut oil

Cortex fraxini was extracted with 95% ethanol to obtain a crude antioxidant extract. The antioxidant activity was evaluated using the linoleic acid peroxidation method and the free radical scavenging assays, namely 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. Cortex fraxini extract (CFE) showed high inhibition of peroxidation of linoleic acid when compared with butylated hydroxytoluene (BHT). CFE also exhibited excellent scavenging activity on DPPH and hydroxyl radicals. Total antioxidant activity was measured by the reduction of Mo(VI) to Mo(V) by the extract, and subsequent formation of a green phosphate/Mo(V) complex at acid pH. CFE had significant total antioxidant activity and the effects were increased with increasing reaction time. The total phenolic content of the sample, analyzed by using Folin–Ciocalteu’s reagent, was 91.33 mg/g dry weight expressed as pyrocatechol equivalents. Then the suitability of CFE as an antioxidant was determined in peanut oil, and the decrease of lipid oxidation was monitored using thiobarbituric acid-reactive substances (TBARS) assay. CFE treatment significantly (P < 0.05) reduced lipid oxidation in peanut oil compared to the control. No significant differences (P = 0.05) in lipid oxidation were detected between CFE antioxidant and BHT antioxidant samples.